1. Technical Field
The invention relates to a valve designed for multiple uses including pressure relief only, topping only, and a combination of pressure relief and topping as needed. More particularly, the invention relates to a combination or hybrid valve for pressure relief and topping applications for use with inflatable devices.
2. Background Information
In recent years, the use of and demand for inflatable devices has grown significantly. Inflatable devices are now commonly used by the military, shipping and airline industries in such specific applications as life rafts, escape slides and rigid-hull inflatable boats often referred to as RIBS.
These inflatable device manufacturers generally utilize a compressed gas charge to inflate the inflatable devices. Specifically, compressed gas is stored in an appropriate pressure tank or cylinder, and it is full, often referred to as pressurized, of carbon dioxide, dry air, nitrogen or a combination of these or similar gases. The volume of gases stored in the cylinder is dependent on the volume of gas required to inflate the inflatable device to the optimum pressure.
To insure proper inflation in cold climate conditions, inflatable device manufacturers must store a larger volume of compressed gas than is required to inflate the device in warm climate conditions. This extra volume/pressure must be released from the inflatable device during warm climate inflation because the inflatable device may be damaged if not relieved.
It is highly recommended and often required that at least one pressure relief valve (PRV) be installed on these inflatable devices to provide for this over-pressure exhausting. This PRV releases the excess volume/pressure. Over-inflation, which may damage or burst the inflation device thereby subjecting the surrounding environment and persons to possible damage and injury, is prevented by this over-pressure exhausting. This release of the fluid contents returns the inflation device to a safe working pressure.
Under different circumstances, the inflatable device will need additional compressed gas to increase the volume/pressure in the inflatable device to the desired levels. This may be due to any of a variety of reasons such as compressed gas level provided being insufficient based upon colder climate than expected, leak in the inflatable device, etc. The additional compressed gas is often provided via a topping valve (sometimes referred to as inflate/deflate valve). This valve is installed in inflatable devices to facilitate the connection of an air pumping mechanism or other compressed gas providing device.